This week's theme is sleep disorders. Does your sleep become more shallow with age? Also, what are "early awakening" and "Awakening Mid-Way"?!
There are four stages of non-REM sleep.
هنالِك أربع مراحل من النّوم غير ر.ي.م
Der Non-REM-Schlaf
hat vier Stufen.
Cette phase comporte quatre stades
Ci sono quattro fasi di sonno non-REM.
Há quatro estágios de sono Não-REM.